The aetiocetus is one of the first baleen whales and is considered as a evolutionary link between the toothed and non- toothed whales. The aetiocetus is believed to have both teeth and baleen and has also exhibited some of the revolutionary links between the modern baleen whales such as the unfused lower jaw bones and a blowhole placed on top of the snout. Recent studies have shown that the blue whale is a close relative of land animals and is closely linked to the hippopotamus.Scientific studies have also shown that the whale ancestors are deer like creatures called Indyhos with a similar appearance to the meerkat.
Habitat
The fossils of the aetiocetus have been discovered in the oceans of North Pacific. They are believed to have appeared around the late Oligocene, approximately 25 million years ago. Scientist believed that aetiocetus habitat in the North Pacific around Oregon, the western side of costal peninsula where the shallow land meets the pacific.
Fossils of the aetiocetus have been found in the outcrops of the seal rock recreation sites inside the North Pacific along with other marine fossils like sea lions, sea cows, sharks and cod-like fi
The coast of the north pacific
sh.This shows the other marine animals that have lived along side with the aetiocetus.
Aetiocetus are thought to be living in the deeper waters of the coast, which was once surrounded by volcanos, which slowly eroded due to pacific storms weathering the coast. The North Pacific was often hit with several hurricans and storms , therefore the volcanos were slowly eroded as time past.
During the Oligocene period the some aetiocetus were thought to have lived in warm, subtropical waters in Oregon. The volcanos around the costal area protected the sea. A modern discovery of oil in the seas of Oregon suggests that the waters were also rich in minerals, providing a good environment for crustaceans and other forms of fish, which the aetiocetus preyed on.
Earth in the Eocene period
Structural adaptations Teeth
The aetiocetus was found to have a forty-four teeth, molars located at the back of the skull along
Labelled diagram of the aetiocetus
with curved canines and incisors. Aetiocetus mostly preyed on slow moving creatures, easily caught as opposed to bigger or faster animals. The teeth are believed to have evolved to help aetiocetus catch prey and allow them to digest their food easily.
The environmental pressure that had given rise may be their change in the variations and forms of their prey over the years, which caused the aetiocetus to have a set of teeth. It also increases their ability to catch their prey as well as consuming it. The teeth could also have been the result of the mixture of two main lineages of early whales .
Jaw bones
The aetiocetus’s jaw was found to have unfused lower jawbones. The unfused lower jaw bones allow the aetiocetus to stretch open their jaws to suck in the water along with small fish. Their upper jaws can also extend towards their skulls forming ridges beneath their eyes. These special jaw bones enable the aetiocetus to feed like today’s modern baleen whales.
The environmental pressure that gave rise to this characteristic could be the change in the forms of the prey causing the aetiocetus to develop unfused jaw bones.It could also have been the prey that the aetiocetus feed on . Because they feed on smaller and slow moving marine animals , the aetiocetus have a unfused jaw bones to consume vast qualities in a shorter time.
Behavioural adaptations Slow movements
The aetiocetus is thought to move slowly because of their prey. It preferred to prey on smaller, slow moving marine animals rather then faster animals. This movement is similar to the blue whales showing how this particular behavioral patter has evolved from .This movement helps the animal to catch smaller prey in the water .
The environmental pressure that has given rise to this behaviour may be the need to conserve energy and the slow moving prey that does not require quick movement to catch. Slow movements could also be a result of not being preyed on , therefore the aetiocetues do not need to move fast to escape .
A reconstruction of the aetiocetus
Feeding patterns
The aetiocetus feed by in taking huge qualities of sea water and trapping small marine animals with their baleen, and then the water was expelled out by the tongue. This type of feed method is also employed by the blue whales . This aids the aetiocetus by helping them intake large qualities of small fish or other marine animals in one glup. It also helps conserve energy and is more suitable because of the size of the aetiocetus , rather then using the common method of chasing and biting down on the prey , this type of feeding is similar to the leopard.
The environmental that pressure could have given rise to this feeding pattern might be the need to intake vast qualities of small marine animals in order to satisfy their diet. In order to replace the energy that is burnt on small marine animals , aetiocetus need to use this method to feed to survival.
Physiological adaptation
Large Orbits
The aetiocetus have specially large orbits located on the top of their jaws. The evidence of the large orbits suggests that the aetiocetus may have relatively large eyeballs . This could mean that atiocetus relieved hevily on their eyesight to hunt . It is specualated that , like the modern whales , the eyes of the aetiocetus are slightly flatter then the normal human eye , which aids them to see better under the water environment. The large eyes could also have helped the aetiocetus to hunt through locating the shorals of small fish and other marine animals.
The environmental pressure that led to relatively large orbits could have been the size of their body. It could also be to make up for their lack of the sense of smell , although scientist have not yet found out if whales have a sense of smell . Another factor that contributes to environmental pressure of having larger eyes could be the need to see better underwater where light is harder to penetrate through water.
Extinction pressure
Change in prey and temperatures of waters
These factors contribute to the extinction of the aetiocetus because their prey changed and evolved therefore the aetiocetus needed to evolve to survive. The temperature of the water also cooled or heated in some places making the environment unsuitable for the aetiocetus.
Another theory that the scientist believe is the cause of the extinction is that the ice age wiped out a vast majority of the animals on Earth which could have included the aetiocetus .The ice age signifacntly changed the tempeture of the sea which could have lead to extinction because they do not have suffient thermoregulation to protect them.Other factors could also have contributed to the extinction of the aetiocetus could be a particular disease that killed most of the population or the species got overrides by other new modern whales with better survival instincts .
General information
The aetiocetus is one of the first baleen whales and is considered as a evolutionary link between the toothed and non- toothed whales. The aetiocetus is believed to have both teeth and baleen and has also exhibited some of the revolutionary links between the modern baleen whales such as the unfused lower jaw bones and a blowhole placed on top of the snout. Recent studies have shown that the blue whale is a close relative of land animals and is closely linked to the hippopotamus.Scientific studies have also shown that the whale ancestors are deer like creatures called Indyhos with a similar appearance to the meerkat.
Habitat
The fossils of the aetiocetus have been discovered in the oceans of North Pacific. They are believed to have appeared around the late Oligocene, approximately 25 million years ago. Scientist believed that aetiocetus habitat in the North Pacific around Oregon, the western side of costal peninsula where the shallow land meets the pacific.
Fossils of the aetiocetus have been found in the outcrops of the seal rock recreation sites inside the North Pacific along with other marine fossils like sea lions, sea cows, sharks and cod-like fi
Aetiocetus are thought to be living in the deeper waters of the coast, which was once surrounded by volcanos, which slowly eroded due to pacific storms weathering the coast. The North Pacific was often hit with several hurricans and storms , therefore the volcanos were slowly eroded as time past.
During the Oligocene period the some aetiocetus were thought to have lived in warm, subtropical waters in Oregon. The volcanos around the costal area protected the sea. A modern discovery of oil in the seas of Oregon suggests that the waters were also rich in minerals, providing a good environment for crustaceans and other forms of fish, which the aetiocetus preyed on.
Structural adaptations
Teeth
The aetiocetus was found to have a forty-four teeth, molars located at the back of the skull along
The environmental pressure that had given rise may be their change in the variations and forms of their prey over the years, which caused the aetiocetus to have a set of teeth. It also increases their ability to catch their prey as well as consuming it. The teeth could also have been the result of the mixture of two main lineages of early whales .
Jaw bones
The aetiocetus’s jaw was found to have unfused lower jawbones. The unfused lower jaw bones allow the aetiocetus to stretch open their jaws to suck in the water along with small fish. Their upper jaws can also extend towards their skulls forming ridges beneath their eyes. These special jaw bones enable the aetiocetus to feed like today’s modern baleen whales.
The environmental pressure that gave rise to this characteristic could be the change in the forms of the prey causing the aetiocetus to develop unfused jaw bones.It could also have been the prey that the aetiocetus feed on . Because they feed on smaller and slow moving marine animals , the aetiocetus have a unfused jaw bones to consume vast qualities in a shorter time.
Behavioural adaptations
Slow movements
The aetiocetus is thought to move slowly because of their prey. It preferred to prey on smaller, slow moving marine animals rather then faster animals. This movement is similar to the blue whales showing how this particular behavioral patter has evolved from .This movement helps the animal to catch smaller prey in the water .
The environmental pressure that has given rise to this behaviour may be the need to conserve energy and the slow moving prey that does not require quick movement to catch. Slow movements could also be a result of not being preyed on , therefore the aetiocetues do not need to move fast to escape .
Feeding patterns
The aetiocetus feed by in taking huge qualities of sea water and trapping small marine animals with their baleen, and then the water was expelled out by the tongue. This type of feed method is also employed by the blue whales . This aids the aetiocetus by helping them intake large qualities of small fish or other marine animals in one glup. It also helps conserve energy and is more suitable because of the size of the aetiocetus , rather then using the common method of chasing and biting down on the prey , this type of feeding is similar to the leopard.
The environmental that pressure could have given rise to this feeding pattern might be the need to intake vast qualities of small marine animals in order to satisfy their diet. In order to replace the energy that is burnt on small marine animals , aetiocetus need to use this method to feed to survival.
Physiological adaptation
Large Orbits
The aetiocetus have specially large orbits located on the top of their jaws. The evidence of the large orbits suggests that the aetiocetus may have relatively large eyeballs . This could mean that atiocetus relieved hevily on their eyesight to hunt . It is specualated that , like the modern whales , the eyes of the aetiocetus are slightly flatter then the normal human eye , which aids them to see better under the water environment. The large eyes could also have helped the aetiocetus to hunt through locating the shorals of small fish and other marine animals.
The environmental pressure that led to relatively large orbits could have been the size of their body. It could also be to make up for their lack of the sense of smell , although scientist have not yet found out if whales have a sense of smell . Another factor that contributes to environmental pressure of having larger eyes could be the need to see better underwater where light is harder to penetrate through water.
Extinction pressure
Change in prey and temperatures of waters
These factors contribute to the extinction of the aetiocetus because their prey changed and evolved therefore the aetiocetus needed to evolve to survive. The temperature of the water also cooled or heated in some places making the environment unsuitable for the aetiocetus.
Another theory that the scientist believe is the cause of the extinction is that the ice age wiped out a vast majority of the animals on Earth which could have included the aetiocetus .The ice age signifacntly changed the tempeture of the sea which could have lead to extinction because they do not have suffient thermoregulation to protect them.Other factors could also have contributed to the extinction of the aetiocetus could be a particular disease that killed most of the population or the species got overrides by other new modern whales with better survival instincts .
Bibliography
Dicovery Media , Aetiocetus , (n.d) , retrived 03/07/2010 , from http://www.servinghistory.com/topics/Aetiocetus
Zipcodezoo , Aetiocus polydentatus, (2004) , 06/07/2010 , from http://zipcodezoo.com/Animals/A/Aetiocetus_polydentatus/
David Rains Wallance , (2007) , Neptune’s ark from Ichthyosaurs to Orcas , http://books.google.com.hk/books?id=829aRxr3JjcC&pg=PA76&lpg=PA76&dq=aetiocetus+adaptation&source=bl&ots=jU1h7Q9-Kn&sig=Y9Dp9IkjtFL6mMtAvTJmUAtwogw&hl=zh-TW&ei=EIJRTJT7EI6ivQOfw4n_BA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBYQ6AEwAA#v=onepage&q=aetiocetus%20adaptation&f=false
Eward Key Babinski , (n.d) , Cetacean Evolution- Evidence Of Common Ancestry of Cetaceans and Certain Species of Land Mammals retrived 23/07/2010 , from http://www.edwardtbabinski.us/whales/evolution_of_whales/